ROME -- - Italian Premier Matteo Renzi announced he will resign Monday after suffering a stinging loss in a reforms referendum, triggering immediate calls from a populist party and other opposition forces for elections to be held soon.

“The ‘No’s’ have won in an extraordinary clear-cut way,” Renzi told reporters in Rome about an hour after polls had closed in Sunday’s balloting.

“I lost and the post that gets eliminated is mine,” Renzi said. “The government’s experience is over, and in the afternoon I’ll go to the Quirinal Hill to hand in my resignation” to President Sergio Mattarella.

Leaders of the populist 5-Star Movement, which is led by comic Beppe Grillo, joined the chorus for early elections. The 5-Stars are the chief rivals of Renzi’s Democrats and are anxious to achieve national power for the first time.

With ballots counted from nearly half of the polling stations, the “No” votes were running at nearly 60 percent to 40 percent for the “Yes” votes on reforms Renzi claimed were vital to modernize Italy.

Mattarella as head of state would have to decide whether to accept any resignation. Renzi is expected to be asked to stay on at least until a budget bill can be passed later this month and to shepherd a months-long electoral reform process.

Opposition leader Matteo Salvini, of the anti-immigrant Northern League, hailed the referendum as a “victory of the people against the strong powers of three-quarters of the world.”

Many had read the referendum as an outlet for growing anti-establishment, populist sentiment in Europe.

The self-assured Renzi late last year pledged to offer his resignation if the referendum on overhauling a good part of the 1948 Constitution went down to defeat.

That was months before Britain’s David Cameron had made his ill-fated bet on the referendum on whether the U.K. should stay in the European Union. He lost that bet.

In Italy, the referendum was required because the reforms were approved by less than two-thirds of Parliament. But Renzi raised the stakes, turning the referendum into a virtual plebiscite on himself, when he pledged to quit if Italians turned their back on reforms to streamline the Senate and give the central government more powers at the cost of the regions.

Some opposition leaders started clamoring for early elections after Renzi’s reform measure went down to defeat.

“We are ready to vote as soon as possible,” Salvini told reporters.

Renzi had been hoping to survive the rising populist forces that have gained traction across Europe.

Some of Renzi’s political opponents were hoping to tap into the populist sentiment that has been gaining ground with the U.K. vote in June to leave the European Union and the U.S. presidential victory last month by billionaire political outsider Donald Trump.

A “Yes” vote would have strengthened Renzi’s 2 ½-year-old government, giving it impetus to complete its five-year term and time to prepare for elections in 2018, while a “No” vote favored early elections sometime next year.

During the referendum campaign, the risk of political instability in Italy, Europe’s fourth-largest economy, triggered market reaction, with bank stocks sinking and borrowing costs on sovereign debt rising.